another hamas building targeted from the sea. all reduced to rubble. in israel on friday, sirens in jerusalem, as the sacred city was targeted for the first time in more than 40 years. a rocket fell ten miles short. no one was hurt. two days in a row, residents of tel aviv, the commercial center, ran for cover, as sirens sounded. >> you know, life is continuing. we're not going to let hamas or other people in gaza to interrupt my way of life. >> reporter: 3 israelis and almost 40 palestinians have been killed in the past 4 days. around half of them, civilians. we saw the wounded rushed to gaza's biggest hospital. its intensive care unit filled with what doctors say are just civilians. are you able to cope if this escalation continues? >> if it continues, we can't. of course, we can't. >> reporter: it looks set to continue, with columns of israeli tanks and troops massing along the border with gaza, fueling fears here of a ground war. the israeli army has also called up 20,000 reservists. israel is clearly preparing for a drawn-out conflict. local autho